Roof rack assemblies are often secured to vehicle roofs for supporting cargo above the roof. Roof rack assemblies often have longitudinally-arranged roof rails. Transverse roof rack bows, sometimes referred to as cross members, may be used to span the distance between the roof rails. Roof rack bows can contribute to aerodynamic drag and wind noise, so some designs allow the bows to be removed from the roof when not in use, or to be stowed in the roof rails. On some vehicles, the transverse distance between the roof rails is greater than a desired fore-aft spacing between the roof rack bows for supporting cargo. Some designs configure the stowed length of the roof rack bows to accommodate the desired fore-aft spacing and allow the roof rack bows to telescope in length to extend between the roof rails when deployed. Telescoping roof rack bows can be difficult for an operator to manually extend so that they reach across the roof between the roof rails.